The Small Firms Association claims that small businesses in Ireland lose over €563m a year through absenteeism.
A total of 3.9m days were lost in small businesses last year through 'sick days'.
A new report from the SFA also shows that workers in small companies are less likely to miss work through illness than their counterparts in larger businesses.
Today's report reveals that the national average for absenteeism is eight days.
This falls to an average of five days for small firms, while a large firm averages ten days.
In terms of regions, the SFA says that the west, northwest and northeast fair badly.
SFA director Avine McNally said back pain and stress are the most commonly cited problems on medical certificates.
Ms McNally said: 'Employers should ensure that they are fulfilling their duty of care to their employees by including manual handling and stress when conducting risk assessments as part of their review of their health and safety statements.'